Association of Benthic Foraminifera with a Gammarid Amphipod on Tidal Flats of San Francisco Bay, California

Abstract

The gammarid amphipod Oligochinus lighti Barnard is an abundant and conspicuous component of the intertidal benthic fauna in San Francisco Bay, California. This crustacean lives protected in an agglutinated tube, feeding mainly on diatoms and smaller metazoans. Five foraminiferal species were observed as epizoans either attached or free-living at the outer surface of the host's tube. The epizoic association of benthic foraminifera with a filter-feeding invertebrate is considered advantageous in terms of access to increased trophic resources, provision of otherwise limited hard substrates, and possibly shelter. Host selection, benefits and constraints of foraminifera/invertebrate associations are reviewed briefly.